PSPICE simulation of current control of an electronically commutated motor

In this paper, a BLDC Motor with 120* voltage source inverter is simulated for various relative positions of back-emf with respect to the Inverter firing signals. Motors with sinusoidal as well as trapezoidal flux distribution signals are considered. The optimal position of back-emf in the routine 120* firing scheme is considered first. Next, a trapezoidal firing scheme is employed to make the machine to act more like a perfect DC motor, with a view to reduce the ripple-torque and improve the output torque, using a near-180* firing scheme. The trapezoidal line to line voltage is obtained using PWM pulses. The entire analysis is carried out by simulation using PSPICE. ©2004 IEEE.